Maize (Zea mays L) is one of the world's important cereal crops. In East Africa, the crop is a major staple food for a large proportion of the population, in addition to being an important animal feed. The importance of maize is centred on the large quantity of carbohydrates, proteins, vitamins and fats, contained in the kernels, making it compare favourably as an energy source with root and tuber crops.
In Uganda, an average of 1.5 tonnes of maize per hectare is produced. Most of this maize, in addition to being eaten directly as food, supports the local brewery industry, where flour is fermented to produce many local brews.
Maize is eaten on cobs, which are either cooked or roasted. Maize flour is also used to prepare a local paste called posho, demand for which is on the increase. Posho is now increasingly served in hotels and restaurants in several urban centres including Kampala City. Maize flour is also used in making porridge for breakfast in many homes in urban areas while the maize itself is used in the manufacture of feeds for livestock.
The maize crop in Africa is white maize – yellow maize is not consumed in the whole of East Africa. Yellow maize can be grown in Africa as the crop grows in similar conditions as those for white maize, but there is no local market for it.
Maize is the third most important cereal crop after sorghum and millet in Uganda. Maize is gradually becoming a very important cereal in Uganda in terms of area under cultivation, production and human consumption. In an average year, maize acreage accounts for about 10% of the total area under annual crops and maize consumption accounts for about 12% of cereals consumption.
Maize is widely grown throughout Uganda, but the main areas are the fertile crescents around the northern periphery of Lake Victoria, the higher altitude areas mostly along the borders, and other fertile areas in the eastern, western and northern districts. Demand for maize has been increasing probably at the expense of other cereals. In Uganda maize is a new social innovation in urban areas (and labour camps) where it has been found to be relatively inexpensive and easily prepared.
In East and Southern Africa, maize accounts for 50% or more of the calories provided by starchy staples in 8 countries (more than 80% of staple calories in Malawi and Zambia) and in many areas it completely dominates the cropping systems of small scale farmers.
Small holders using hand tools and little or no purchased inputs mainly produce maize. The low level of technology used in production means that the yields are low and the production process is aimed mainly at providing subsistence requirements with very little surplus for sale. Maize yields are still low averaging about 1.3 tonnes per hectare as compared to the yield potential of about 3-4 tonnes per hectare. Low yields are attributed to low use of technology, heavy reliance on natural conditions, traditional production systems e.g. use of farm saved seed and rudimentary tools.
Losses of maize occur throughout the post harvest system i.e. harvesting, storing and processing right up to consumption. Harvesting is manually done using either hand/finger knife, panga or dislodging cobs from the main plant. The harvest is then carried home where drying is done on bare ground.
The most common traditional practice of drying involves leaving cobs to dry on the mother plant in the field; stocking harvested crop in the field, spreading the crop on well levelled bare ground, stabilised ground. Drying is solely dependent on sunshine, and hence limited to only daytime and non-rainy periods.
The grain for consumption or storage is prepared by shelling. Traditionally shelling is done by either, prising the grain off the cob with the thumbs, rubbing two cobs together holding one in each hand or beating the cobs in a sack with a stick. The above methods are labour intensive, time consuming and wasteful. Furthermore, beating breaks the grain and reduces seed viability.
The grain is then milled into flour and made into a paste called posho. Maize is stored in many smaller containers at the household level for later consumption. These include gunny bags (by far the most common), gourds, clay pots, mud/straw compartments, woven reed/straw baskets, metal/plastic containers, basins and drums.
Maize is stored either in the unshelled or shelled form. Those who store it in the unshelled form claim that insect damage is reduced, whilst those who store it in the shelled form, do so to ease the application of insecticides in order to prevent insect damage. Early sales are made for cash and for fear of insect and rodent damage.